The first century Jewish historian Josephus proclaimed a connection between the twelve stones in Aaron's breastplate, the twelve months of the year and the twelve signs of the zodiac. Translations and interpretations of the passage in Exodus regarding the breastplate have varied widely, however, with Josephus himself giving two different lists for the twelve stones (Kunz argues that Josephus saw the breastplate of the Second Temple, not the one described in Exodus). St. Jerome, referencing Josephus, said the Foundation Stones of the New Jerusalem (Revelations 21:19-20) would be appropriate for Christians to use. In the eight and ninth century religious treaties were written associating a particular stone with an apostle, as Revelations stated their name would be inscribed on the Foundation Stones, and his virtue. Practice became to keep twelve stones and wear one a month. Wearing a single birthstone is only a few centuries old, although modern authorities differ on dates: Kunz places the custom in eighteenth century Poland, while the Gemological Institute of America starts it in Germany in the 1560s.

Modern lists of birthstones have little to do with either the breastplate or the Foundation Stones of Christianity. Tastes, customs and confusing translations have distanced them from their historical origins, with one author calling the Kansas list "nothing but a piece of unfounded salesmanship."

Modern birthstones

In 1912, in an effort to standardize birthstones, the (American) National Association of Jewelers officially adopted a list, shown in the "Modern" column of the table shown in the next section.

The most recent change to the birthstone list occurred in October of 2002, with the addition of tanzanite as a December birthstone.